Image processing system, apparatus, and method and medical image diagnosis apparatus

ABSTRACT

In an image processing system according to an embodiment, a display unit simultaneously displays a predetermined number of parallax images. A parallax image generation control unit performs control such that a group of parallax images of point-of-view positions which are larger in number than the predetermined number is generated. A display control unit classifies the group of the parallax images into a first parallax image sub group including a set of parallax images whose point-of-view positions are discontinuous to each other and a second parallax image sub group including parallax images whose point-of-view positions are between the set of the parallax images, and performs control such that the display unit displays the first parallax image sub group and the second parallax image sub group while switching the first parallax image sub group and the second parallax image sub group at a predetermined switching speed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2011-160071, filed on Jul. 21, 2011; theentire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to an image processingsystem, apparatus, and method, and a medical image diagnosis apparatus.

BACKGROUND

Conventionally, monitors enabling an observer to view two-parallaximages captured from two viewpoints stereoscopically by using a specificdevice, such as a pair of stereoscopic vision glasses, have been inpractical use. Furthermore, in recent years, monitors enabling anobserver to view multi-parallax images (e.g., nine-parallax images)captured from a plurality of viewpoints stereoscopically with the nakedeyes by using a beam control element, such as a lenticular lens, havealso been in practical use. Such two-parallax images and nine-parallaximages displayed on monitors enabling stereoscopic vision may begenerated by estimating depth information of an image captured from oneviewpoint and performing image processing with the information thusestimated.

As for medical image diagnosis apparatuses, such as X-ray computedtomography (CT) apparatuses, magnetic resonance imaging (MRI)apparatuses, and ultrasound diagnosis apparatuses, apparatuses capableof generating three-dimensional medical image data (hereinafter,referred to as volume data) have been in practical use. Conventionally,volume data generated by such a medical image diagnosis apparatus isconverted into a two-dimensional image by various types of imageprocessing, and is displayed two-dimensionally on a general-purposemonitor. For example, volume data generated by a medical image diagnosisapparatus is converted into a two-dimensional image that reflectsthree-dimensional information by volume rendering processing, and isdisplayed two-dimensionally on a general-purpose monitor.

In the conventional technology, however, there is a certain limit to adegree of the depth of the stereoscopically viewable image.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram for describing a configuration example of an imageprocessing system according to a first embodiment;

FIGS. 2A and 2B are diagrams for describing an example of a stereoscopicdisplay monitor that performs a stereoscopic display based on atwo-parallax image;

FIG. 3 is a diagram for describing an example of a stereoscopic displaymonitor that performs a stereoscopic display based on a nine-parallaximage;

FIG. 4 is a diagram for describing a configuration example of aworkstation according to the first embodiment;

FIG. 5 is a diagram for describing a configuration example of arendering processing unit illustrated in FIG. 4;

FIG. 6 is a diagram for describing an example of a volume renderingprocess according to the first embodiment;

FIG. 7 is a first diagram for describing a problem of the related art;

FIG. 8 is a second diagram for describing a problem of the related art;

FIG. 9 is a diagram for describing an example of a technique ofimproving a degree of the depth of a stereoscopic image having no blur;

FIG. 10 is a diagram for describing a configuration example of a controlunit according to the first embodiment;

FIG. 11 is a diagram for describing an example of a process performed bya rendering control unit according to the first embodiment;

FIG. 12A is a diagram for describing an example of a first displayprocess performed by a display control unit according to the firstembodiment;

FIG. 12B is a diagram for describing an example of a second displayprocess performed by a display control unit according to the firstembodiment;

FIG. 13 is a flow chart illustrating a procedure of a process performedby a workstation according to the first embodiment;

FIG. 14 is a schematic view for describing an outline of a processexecuted by a display control unit according to a second embodiment;

FIG. 15 is a diagram for describing an example of a process performed bya display control unit according to the second embodiment;

FIG. 16 is a flow chart illustrating a procedure of a process performedby a workstation according to the second embodiment; and

FIG. 17 is a diagram for describing deviation correction by sliding alenticular lens according to a third embodiment.

DETAILED DESCRIPTION

According to an embodiment, an image processing system includes adisplay unit, a parallax image generation control unit and a displaycontrol unit. The display unit configured to simultaneously display apredetermined number of parallax image. The parallax image generationcontrol unit configured to perform control such that a group of parallaximages of point-of-view positions which are larger in number than thepredetermined number is generated. The display control unit configuredto classify the group of the parallax images generated by control of theparallax image generation control unit into a first parallax image subgroup including a set of parallax images whose point-of-view positionsare discontinuous to each other and a second parallax image sub groupincluding parallax images whose point-of-view positions are between theset of the parallax images, and perform control such that the displayunit displays the first parallax image sub group and the second parallaximage sub group while switching the first parallax image sub group andthe second parallax image sub group at a predetermined switching speed.

Hereinafter, embodiments of an image processing system, apparatus, andmethod will be described in detail with reference to the accompanyingdrawings. In the following, an image processing system including aworkstation with a function as an image processing apparatus isdescribed as an embodiment. Here, the terminology used in the followingembodiments is described. A “parallax image group” refers to an imagegroup which is generated by performing a volume rendering process onvolume data while moving a point-of-view position by a predeterminedparallactic angle at a time. In other words, the “parallax image group”is configured with a plurality of “parallax images” having different“point-of-view positions.” Further, a “parallactic angle” refers to anangle determined by an adjacent point-of-view position amongpoint-of-view positions set to generate the “parallax image group” and apredetermined position in a space (the center of a space) represented byvolume data. Further, a “parallax number” refers to the number of“parallax images” necessary to implement a stereoscopic view by astereoscopic display monitor. Further, a “nine-parallax image” describedin the following refers to a “parallax image group” consisting of nine“parallax images.” Furthermore, a “two-parallax image” described in thefollowing refers to a “parallax image group” consisting of two “parallaximages.”

First Embodiment

First, a configuration example of an image processing system accordingto a first embodiment will be described. FIG. 1 is a diagram forexplaining an exemplary configuration of an image processing systemaccording to a first embodiment.

As illustrated in FIG. 1, an image processing system 1 according to thefirst embodiment includes a medical image diagnosis apparatus 110, animage storage device 120, a workstation 130, and a terminal device 140.The respective devices illustrated in FIG. 1 are connected to directlyor indirectly communicate one another, for example, via a hospital LocalArea Network (LAN) 2 installed in a hospital. For example, when aPicture Archiving and Communication System (PACS) is introduced into theimage processing system 1, the respective devices exchange a medicalimage or the like with one another according to a Digital Imaging andCommunications in Medicine (DICOM) standard.

The image processing system 1 generates a parallax image group fromvolume data, which is three-dimensional medical image data, generated bythe medical image diagnosis apparatus 110, and displays the parallaximage group on a monitor enabling stereoscopic vision. Thus, the imageprocessing system 1 provides a medical image capable of being viewedstereoscopically to a doctor or a laboratory technician who works forthe hospital. Specifically, in the first embodiment, the workstation 130performs various types of image processing on volume data to generate aparallax image group. The workstation 130 and the terminal device 140have a monitor enabling stereoscopic vision, and display the parallaximage group generated by the workstation 130 on the monitor. The imagestorage device 120 stores therein the volume data generated by themedical image diagnosis apparatus 110 and the parallax image groupgenerated by the workstation 130. In other words, the workstation 130and the terminal device 140 acquire the volume data and the parallaximage group from the image storage device 120 to process the volume dataand to display the parallax image group on the monitor. The devices willbe explained below in order.

The medical image diagnosis apparatus 110 is an X-ray diagnosisapparatus, an X-ray Computed Tomography (CT) apparatus, a MagneticResonance Imaging (MRI) apparatus, an ultrasonic diagnostic device, aSingle Photon Emission Computed Tomography (SPECT) device, a PositronEmission computed Tomography (PET) apparatus, a SPECT-CT apparatus inwhich a SPECT apparatus is integrated with an X-ray CT apparatus, aPET-CT apparatus in which a PET apparatus is integrated with an X-ray CTapparatus, a device group thereof, or the like. The medical imagediagnosis apparatus 110 according to the first embodiment can generate3D medical image data (volume data).

Specifically, the medical image diagnosis apparatus 110 according to thefirst embodiment captures a subject, and generates volume data. Forexample, the medical image diagnosis apparatus 110 generates volume datasuch that it collects data such as projection data or an MR signal bycapturing a subject, and then reconstructs medical image data includinga plurality of axial planes along a body axis direction of a subjectbased on the collected data. The medical image diagnosis apparatus 110reconstructs medical image data of 500 axial planes, for example. Themedical image data group of 500 axial planes corresponds to volume data.Alternatively, projection data or an MR signal of a subject captured bythe medical image diagnosis apparatus 110 may be used as volume data.

The medical image diagnosis apparatus 110 according to the firstembodiment transmits the generated volume data to the image storagedevice 120. When the medical image diagnosis apparatus 110 transmits thevolume data to the image storage device 120, the medical image diagnosisapparatus 110 transmits supplementary information such as a patient IDidentifying a patient, an inspection ID identifying an inspection, aapparatus ID identifying the medical image diagnosis apparatus 110, anda series ID identifying single shooting by the medical image diagnosisapparatus 110, for example.

The image storage device 120 is a database that stores a medical image.Specifically, the image storage device 120 according to the firstembodiment stores volume data transmitted from the medical imagediagnosis apparatus 110 in a storage unit to store the volume datatherein. Further, in the first embodiment, the workstation 130 generatesa parallax image group based on the volume data, and transmits thegenerated parallax image group to the image storage device 120. Thus,the image storage device 120 stores a parallax image group transmittedfrom the workstation 130 in the storage unit to store the parallax imagegroup therein. Further, in the present embodiment, the workstation 130capable of storing a large amount of images may be used, and in thiscase, the image storage device 120 illustrated in FIG. 1 may beincorporated with the workstation 130 illustrated in FIG. 1. In otherwords, in the present embodiment, the volume data or the parallax imagegroup may be stored in the workstation 130.

Further, in the first embodiment, the volume data or the parallax imagegroup stored in the image storage device 120 is stored in associationwith the patient ID, the inspection ID, the apparatus ID, the series ID,and the like. Thus, the workstation 130 or the terminal device 140performs a search using the patient ID, the inspection ID, the apparatusID, the series ID, or the like, and acquires necessary volume data or anecessary parallax image group from the image storage device 120.

The workstation 130 is an image processing apparatus that performs imageprocessing on a medical image. Specifically, the workstation 130according to the first embodiment performs various types of renderingprocessing on the volume data acquired from the image storage device 120to generate a parallax image group. The parallax image group is aplurality of parallax images captured from a plurality of viewpoints. Aparallax image group displayed on a monitor enabling an observer to viewnine-parallax images stereoscopically with the naked eyes is nineparallax images whose viewpoint positions are different from oneanother.

The workstation 130 according to the first embodiment includes a monitorenabling stereoscopic vision (hereinafter, referred to as a stereoscopicdisplay monitor) as a display unit. The workstation 130 generates aparallax image group, and displays the parallax image group thusgenerated on the stereoscopic display monitor. As a result, an operatorof the workstation 130 can perform an operation for generating theparallax image group while checking a medical image that is displayed onthe stereoscopic display monitor and capable of being viewedstereoscopically.

The workstation 130 transmits the parallax image group thus generated tothe image storage device 120. When transmitting the parallax image groupto the image storage device 120, the workstation 130 transmits thepatient ID, the examination ID, the apparatus ID, and the series ID, forexample, as additional information. Examples of the additionalinformation transmitted when the workstation 130 transmits the parallaximage group to the image storage device 120 include additionalinformation related to the parallax image group. Examples of theadditional information related to the parallax image group include thenumber of parallax images (e.g., “nine”) and the resolution of theparallax image (e.g., “466×350 pixels”).

To generate and display multi-parallax images sequentially, theworkstation 130 according to the first embodiment generates and displaysparallax images of different parallax positions alternately betweencontinuous time-phase data. As a result, the workstation 130 can displaysequential multi-parallax images smoothly even if the sequentialmulti-parallax images are generated and displayed in real time. Thisoperation will be described later in detail.

The terminal device 140 is a device that allows a doctor or a laboratorytechnician who works in the hospital to view a medical image. Examplesof the terminal device 140 include a Personal Computer (PC), atablet-type PC, a Personal Digital Assistant (PDA), and a portabletelephone, which are operated by a doctor or a laboratory technician whoworks in the hospital. Specifically, the terminal device 140 accordingto the first embodiment includes a stereoscopic display monitor as adisplay unit. Further, the terminal device 140 acquires a parallax imagegroup from the image storage device 120, and causes the acquiredparallax image group to be displayed on the stereoscopic displaymonitor. As a result, a doctor or a laboratory technician who is anobserver can view a stereoscopically viewable medical image.

Here, the stereoscopic display monitor included in the workstation 130or the terminal device 140 will be described. A general-purpose monitorwhich is currently most widely used two dimensionally displays atwo-dimensional (2D) image and hardly performs a 3D display on a 2Dimage. If an observer desires a stereoscopic view to be displayed on thegeneral-purpose monitor, a device that outputs an image to thegeneral-purpose monitor needs to parallel-display a two-parallax imagestereoscopically viewable to an observer through a parallel method or anintersection method. Alternatively, a device that outputs an image tothe general-purpose monitor needs to display an image stereoscopicallyviewable to an observer through a color-complementation method usingglasses in which a red cellophane is attached to a left-eye portion anda blue cellophane is attached to a right-eye portion.

Meanwhile, there are stereoscopic display monitors that allow atwo-parallax image (which is also referred to as a “binocular parallaximage”) to be stereoscopically viewed using a dedicated device such asstereoscopic glasses.

FIG. 2A and FIG. 2B are schematics for explaining an example of astereoscopic display monitor that performs stereoscopic display usingtwo-parallax images. In the example illustrated in FIGS. 2A and 2B, thestereoscopic display monitor performs a stereoscopic display by ashutter method, and shutter glasses are used as stereoscopic glassesworn by an observer who observes the monitor. The stereoscopic displaymonitor alternately outputs a two-parallax image in the monitor. Forexample, the monitor illustrated in FIG. 2A alternately outputs aleft-eye image and a right-eye image with 120 Hz. As illustrated in FIG.2A, the monitor includes an infrared-ray output unit, and controls anoutput of an infrared ray according to a timing at which images areswitched.

The infrared ray output from the infrared-ray output unit is received byan infrared-ray receiving unit of the shutter glasses illustrated inFIG. 2A. A shutter is mounted to each of right and left frames of theshutter glasses, and the shutter glasses alternately switch atransmission state and a light shielding state of the right and leftshutters according to a timing at which the infrared-ray receiving unitreceives the infrared ray. A switching process of a transmission stateand a light shielding state of the shutter will be described below.

As illustrated in FIG. 2B, each shutter includes an incident sidepolarizing plate and an output side polarizing plate, and furtherincludes a liquid crystal layer disposed between the incident sidepolarizing plate and the output side polarizing plate. The incident sidepolarizing plate and the output side polarizing plate are orthogonal toeach other as illustrated in FIG. 2B. Here, as illustrated in FIG. 2B,in an OFF state in which a voltage is not applied, light has passedthrough the incident side polarizing plate rotates at 90° due to anoperation of the liquid crystal layer, and passes through the outputside polarizing plate. In other words, the shutter to which a voltage isnot applied becomes a transmission state.

Meanwhile, as illustrated in FIG. 2B, in an ON state in which a voltageis applied, a polarization rotation operation caused by liquid crystalmolecules of the liquid crystal layer does not work, and thus lighthaving passed through the incident side polarizing plate is shielded bythe output side polarizing plate. In other words, the shutter to which avoltage is applied becomes a light shielding state.

In this regard, for example, the infrared-ray output unit outputs theinfrared ray during a time period in which the left-eye image is beingdisplayed on the monitor. Then, during a time period in which theinfrared ray is being received, the infrared-ray receiving unit appliesa voltage to the right-eye shutter without applying a voltage to theleft-eye shutter. Through this operation, as illustrated in FIG. 2A, theright-eye shutter becomes the light shielding state, and the left-eyeshutter becomes the transmission state, so that the left-eye image isincident to the left eye of the observer. Meanwhile, during a timeperiod in which the right-eye image is being displayed on the monitor,the infrared-ray output unit stops an output of the infrared ray. Then,during a time period in which the infrared ray is not being received,the infrared-ray receiving unit applies a voltage to the left-eyeshutter without applying a voltage to the right-eye shutter. Throughthis operation, the left-eye shutter becomes the light shielding state,and the right-eye shutter becomes the transmission state, so that theright-eye image is incident to the right eye of the observer. Asdescribed above, the stereoscopic display monitor illustrated in FIGS.2A and 2B causes an image stereoscopically viewable to the observer tobe displayed by switching an image to be displayed on the monitor inconjunction with the state of the shutter. A monitor employing apolarizing glasses method other than the shutter method is also known asthe stereoscopic display monitor that allows a two-parallax image to bestereoscopically viewed.

Further, a stereoscopic display monitor that allows an observer tostereoscopically view a multi-parallax image with the naked eyes such asa nine-parallax image using a light beam controller such as a lenticularlens has been recently put to practical. This kind of stereoscopicdisplay monitor makes a stereoscopic view possible by binocularparallax, and further makes a stereoscopic view possible by kinematicparallax in which an observed video changes with the movement of a pointof view of an observer.

FIG. 3 is a schematic for explaining an example of a stereoscopicdisplay monitor that performs stereoscopic display using nine-parallaximages. In the stereoscopic display monitor illustrated in FIG. 3, alight beam controller is arranged in front of a planar display surface200 such as a liquid crystal panel. For example, in the stereoscopicdisplay monitor illustrated in FIG. 3, a vertical lenticular sheet 201including an optical opening that extends in a vertical direction isattached to the front surface of the display surface 200 as the lightbeam controller.

As illustrated in FIG. 3, in the display surface 200, an aspect ratio is3:1, and pixels 202 each of which includes three sub-pixels of red (R),green (G), and blue (B) arranged in a longitudinal direction arearranged in the form of a matrix. The stereoscopic display monitorillustrated in FIG. 3 converts a nine-parallax image including nineimages into an interim image arranged in a predetermined format (forexample, in a lattice form), and outputs the interim image to thedisplay surface 200. In other words, the stereoscopic display monitorillustrated in FIG. 3 allocates nine pixels at the same position in thenine-parallax image to the pixels 202 of nine columns, respectively, andthen performs an output. The pixels 202 of nine columns become a unitpixel group 203 to simultaneously display nine images having differentpoint-of-view positions.

The nine-parallax image simultaneously output as the unit pixel group203 in the display surface 200 is radiated as parallel light through aLight Emitting Diode (LED) backlight, and further radiated in multipledirections through the vertical lenticular sheet 201. As light of eachpixel of the nine-parallax image is radiated in multiple directions,lights incident to the left eye and the right eye of the observer changein conjunction with the position (the position of the point of view) ofthe observer. In other words, depending on an angle at which theobserver views, a parallax image incident to the right eye differs in aparallactic angle from a parallax image incident to the left eye.Through this operation, the observer can stereoscopically view ashooting target, for example, at each of nine positions illustrated inFIG. 3. For example, the observer can stereoscopically view, in a statein which the observer directly faces a shooting target, at the positionof “5” illustrated in FIG. 3, and can stereoscopically view, in a statein which a direction of a shooting target is changed, at the positionsother than “5” illustrated in FIG. 3. The stereoscopic display monitorillustrated in FIG. 3 is merely an example. The stereoscopic displaymonitor that displays the nine-parallax image may include a horizontalstripe liquid crystal of “RRR - - - , GGG - - - , and BBB - - - ” asillustrated in FIG. 3 or may include a vertical stripe liquid crystal of“RGBRGB - - - .” Further, the stereoscopic display monitor illustratedin FIG. 3 may be of a vertical lens type in which a lenticular sheet isvertical as illustrated in FIG. 3 or may be of an oblique lens type inwhich a lenticular sheet is oblique.

The configuration example of the image processing system 1 according tothe first embodiment has been briefly described so far. An applicationof the image processing system 1 described above is not limited to acase in which the PACS is introduced. For example, the image processingsystem 1 is similarly applied even to a case in which an electronicchart system for managing an electronic chart with a medical imageattached thereto is introduced. In this case, the image storage device120 serves as a database for managing an electronic chart. Further, forexample, the image processing system 1 is similarly applied even to acase in which a Hospital Information System (HIS) or RadiologyInformation System (RIS) is introduced. Further, the image processingsystem 1 is not limited to the above-described configuration example. Afunction or an assignment of each device may be appropriately changedaccording to an operation form.

Next, a configuration example of a workstation according to the firstembodiment will be described with reference to FIG. 4. FIG. 4 is adiagram for explaining an exemplary configuration of a workstationaccording to the first embodiment. In the following, a “parallax imagegroup” refers to an image group for a stereoscopic view generated byperforming a volume rendering process on volume data. Further, a“parallax image” refers to each of images that configure the “parallaximage group.” In other words, the “parallax image group” is configuredwith a plurality of “parallax images” having different point-of-viewpositions.

The workstation 130 according to the first embodiment is ahigh-performance computer appropriate to image processing or the like,and includes an input unit 131, a display unit 132, a communication unit133, a storage unit 134, a control unit 135, and a rendering processingunit 136 as illustrated in FIG. 4. In the following, a description willbe made in connection with an example in which the workstation 130 is ahigh-performance computer appropriate to image processing or the like.However, the workstation 130 is not limited to this example, and may bean arbitrary information processing device. For example, the workstation130 may be an arbitrary personal computer.

The input unit 131 includes a mouse, a keyboard, a trackball, or thelike, and receives various operations which an operator has input on theworkstation 130. Specifically, the input unit 131 according to the firstembodiment receives an input of information used to acquire volume datawhich is a target of the rendering process from the image storage device120. For example, the input unit 131 receives an input of the patientID, the inspection ID, the apparatus ID, the series ID, or the like.Further, the input unit 131 according to the first embodiment receivesan input of a condition (hereinafter, referred to as a “renderingcondition”) related to the rendering process.

The display unit 132 includes a liquid crystal panel serving as astereoscopic display monitor, and displays a variety of information.Specifically, the display unit 132 according to the first embodimentdisplays a Graphical User Interface (GUI), which is used to receivevarious operations from the operator, a parallax image group, or thelike. The communication unit 133 includes a Network Interface Card (NIC)or the like and performs communication with other devices.

The storage unit 134 includes a hard disk, a semiconductor memorydevice, or the like, and stores a variety of information. Specifically,the storage unit 134 according to the first embodiment stores the volumedata acquired from the image storage device 120 through thecommunication unit 133. Further, the storage unit 134 according to thefirst embodiment stores volume data which is under the renderingprocess, a parallax image group generated by the rendering process, orthe like.

The control unit 135 includes an electronic circuit such as a CentralProcessing Unit (CPU), a Micro Processing Unit (MPU), or a GraphicsProcessing Unit (GPU) or an integrated circuit such as an ApplicationSpecific Integrated Circuit (ASIC) or a Field Programmable Gate Array(FPGA). The control unit 135 controls the workstation 130 in general.

For example, the control unit 135 according to the first embodimentcontrols a display of the GUI on the display unit 132 or a display of aparallax image group. Further, for example, the control unit 135controls transmission/reception of the volume data or the parallax imagegroup to/from the image storage device 120, which is performed throughthe communication unit 133. Further, for example, the control unit 135controls the rendering process performed by the rendering processingunit 136. Further, for example, the control unit 135 controls anoperation of reading volume data from the storage unit 134 or anoperation of storing a parallax image group in the storage unit 134.

In the first embodiment, the control unit 135 of the workstation 130controls the rendering processing performed by the rendering processingunit 136, and cooperates with the rendering processing unit 136. Thus,the control unit 135 generates parallax images of different parallaxpositions alternately between continuous time-phase data and displaysthe parallax images on the display unit 132. This operation will bedescribed later in detail.

The rendering processing unit 136 performs various rendering processeson volume data acquired from the image storage device 120 under controlof the control unit 135, and thus generates a parallax image group.Specifically, the rendering processing unit 136 according to the firstembodiment reads volume data from the storage unit 134, and firstperforms pre-processing on the volume data. Next, the renderingprocessing unit 136 performs a volume rendering process on thepre-processed volume data, and generates a parallax image group.Subsequently, the rendering processing unit 136 generates a 2D image inwhich a variety of information (a scale, a patient name, an inspectionitem, and the like) is represented, and generates a 2D output image bysuperimposing the 2D image on each parallax image group. Then, therendering processing unit 136 stores the generated parallax image groupor the 2D output image in the storage unit 134. Further, in the firstembodiment, the rendering process refers to the entire image processingperformed on the volume data, and the volume rendering process a processof generating a 2D image in which 3D information is reflected during therendering process. For example, the medical image generated by therendering process corresponds to a parallax image.

FIG. 5 is a diagram for explaining an exemplary configuration of arendering processing unit illustrated in FIG. 4. As illustrated in FIG.5, the rendering processing unit 136 includes a pre-processing unit1361, a 3D image processing unit 1362, and a 2D image processing unit1363. The pre-processing unit 1361 performs pre-processing on volumedata. The 3D image processing unit 1362 generates a parallax image groupfrom pre-processed volume data. The 2D image processing unit 1363generates a 2D output image in which a variety of information issuperimposed on a parallax image group. The respective units will bedescribed below in order.

The pre-processing unit 1361 is a processing unit that performs avariety of pre-processing when performing the rendering process onvolume data, and includes an image correction processing unit 1361 a, a3D object fusion unit 1361 e, and a 3D object display area setting unit1361 f.

The image correction processing unit 1361 a is a processing unit thatperforms an image correction process when processing two types of volumedata as one volume data, and includes a distortion correction processingunit 1361 b, a body motion correction processing unit 1361 c, and aninter-image positioning processing unit 1361 d as illustrated in FIG. 5.For example, the image correction processing unit 1361 a performs animage correction process when processing volume data of a PET imagegenerated by a PET-CT apparatus and volume data of an X-ray CT image asone volume data. Alternatively, the image correction processing unit1361 a performs an image correction process when processing volume dataof a T1-weighted image and volume data of a T2-weighted image which aregenerated by an MRI apparatus as one volume data.

Further, the distortion correction processing unit 1361 b correctsdistortion of individual volume data caused by a collection condition atthe time of data collection by the medical image diagnosis apparatus110. Further, the body motion correction processing unit 1361 c correctsmovement caused by body motion of a subject during a data collectiontime period used to generate individual volume data. Further, theinter-image positioning processing unit 1361 d performs positioning(registration), for example, using a cross correlation method betweentwo pieces of volume data which have been subjected to the correctionprocesses by the distortion correction processing unit 1361 b and thebody motion correction processing unit 1361 c.

The 3D object fusion unit 1361 e performs the fusion of a plurality ofvolume data which have been subjected to the positioning by theinter-image positioning processing unit 1361 d. Further, the processesperformed by the image correction processing unit 1361 a and the 3Dobject fusion unit 1361 e may not be performed when the renderingprocess is performed on single volume data.

The 3D object display area setting unit 1361 f is a processing unit thatsets a display area corresponding to a display target organ designatedby an operator, and includes a segmentation processing unit 1361 g. Thesegmentation processing unit 1361 g is a processing unit that extractsan organ, such as a heart, a lung, or a blood vessel, which isdesignated by the operator, for example, by an area extension techniquebased on a pixel value (voxel value) of volume data.

Further, the segmentation processing unit 1361 g does not perform thesegmentation process when a display target organ has not been designatedby the operator. Further, the segmentation processing unit 1361 gextracts a plurality of corresponding organs when a plurality of displaytarget organs is designated by the operator. Further, the processperformed by the segmentation processing unit 1361 g may be re-executedat a fine adjustment request of the operator who has referred to arendering image.

The 3D image processing unit 1362 performs the volume rendering processon the pre-processed volume data which has been subjected to the processperformed by the pre-processing unit 1361. As processing units forperforming the volume rendering process, the 3D image processing unit1362 includes a projection method setting unit 1362 a, a 3D geometrictransform processing unit 1362 b, a 3D object appearance processing unit1362 f, and a 3D virtual space rendering unit 1362 k.

The projection method setting unit 1362 a determines a projection methodfor generating a parallax image group. For example, the projectionmethod setting unit 1362 a determines whether the volume renderingprocess is to be executed using a parallel projection method or aperspective projection method.

The 3D geometric transform processing unit 1362 b is a processing unitthat determines information necessary to perform 3D geometric transformon volume data which is to be subjected to the volume rendering process,and includes a parallel shift processing unit 1362 c, a rotationprocessing unit 1362 d, and a scaling processing unit 1362 e. Theparallel shift processing unit 1362 c is a processing unit thatdetermines a shift amount to shift volume data in parallel when apoint-of-view position is shifted in parallel at the time of the volumerendering process. The rotation processing unit 1362 d is a processingunit that determines a movement amount for rotationally moving volumedata when a point-of-view position is rotationally moved at the time ofthe volume rendering process. Further, the scaling processing unit 1362e is a processing unit that determines an enlargement ratio or areduction ratio of volume data when it is requested to enlarge or reducea parallax image group.

The 3D object appearance processing unit 1362 f includes a 3D objectcolor processing unit 1362 g, a 3D object opacity processing unit 1362h, a 3D object quality-of-material processing unit 1362 i, and a 3Dvirtual space light source processing unit 1362 j. The 3D objectappearance processing unit 1362 f performs a process of determining adisplay form of a parallax image group to be displayed through the aboveprocessing units, for example, according to the operator's request.

The 3D object color processing unit 1362 g is a processing unit thatdetermines a color colored to each area segmented from volume data. The3D object opacity processing unit 1362 h is a processing unit thatdetermines opacity of each voxel configuring each area segmented fromvolume data. In volume data, an area behind an area having opacity of“100%” is not represented in a parallax image group. Further, in volumedata, an area having opacity of “0%” is not represented in a parallaximage group.

The 3D object quality-of-material processing unit 1362 i is a processingunit that determines the quality of a material of each area segmentedfrom volume data and adjusts the texture when the area is represented.The 3D virtual space light source processing unit 1362 j is a processingunit that determines the position or the type of a virtual light sourceinstalled in a 3D virtual space when the volume rendering process isperformed on volume data. Examples of the type of a virtual light sourceinclude a light source that emits a parallel beam from infinity and alight source that emits a radial beam from a point of view.

The 3D virtual space rendering unit 1362 k performs the volume renderingprocess on volume data, and generates a parallax image group. Further,the 3D virtual space rendering unit 1362 k uses a variety ofinformation, which is determined by the projection method setting unit1362 a, the 3D geometric transform processing unit 1362 b, and the 3Dobject appearance processing unit 1362 f, as necessary when the volumerendering process is performed.

Here, the volume rendering process performed by the 3D virtual spacerendering unit 1362 k is performed according to the rendering condition.For example, the parallel projection method or the perspectiveprojection method may be used as the rendering condition. Further, forexample, a reference point-of-view position, a parallactic angle, and aparallax number may be used as the rendering condition. Further, forexample, a parallel shift of a point-of-view position, a rotationalmovement of a point-of-view position, an enlargement of a parallax imagegroup, and a reduction of a parallax image group may be used as therendering condition. Further, for example, a color colored,transparency, the texture, the position of a virtual light source, andthe type of virtual light source may be used as the rendering condition.The rendering condition may be input by the operator through the inputunit 131 or may be initially set. In either case, the 3D virtual spacerendering unit 1362 k receives the rendering condition from the controlunit 135, and performs the volume rendering process on volume dataaccording to the rendering condition. Further, at this time, theprojection method setting unit 1362 a, the 3D geometric transformprocessing unit 1362 b, and the 3D object appearance processing unit1362 f determine a variety of necessary information according to therendering condition, and thus the 3D virtual space rendering unit 1362 kgenerates a parallax image group using a variety of informationdetermined.

FIG. 6 is a schematic for explaining an example of volume renderingprocessing according to the first embodiment. For example, let us assumethat the 3D virtual space rendering unit 1362 k receives the parallelprojection method as the rendering condition, and further receives areference point-of-view position (5) and a parallactic angle “1°” asillustrated in a “nine-parallax image generating method (1)” of FIG. 6.In this case, the 3D virtual space rendering unit 1362 k shifts theposition of a point of view to (1) to (9) in parallel so that theparallactic angle can be changed by “1°”, and generates nine parallaximages between which the parallactic angle (an angle in a line-of-sightdirection) differs from each other by 1° by the parallel projectionmethod. Further, when the parallel projection method is performed, the3D virtual space rendering unit 1362 k sets a light source that emits aparallel beam in a line-of-sight direction from infinity.

Alternatively, the 3D virtual space rendering unit 1362 k receives theperspective projection method as the rendering condition, and furtherreceives a reference point-of-view position (5) and a parallactic angle“1°” as illustrated in a “nine-parallax image generating method (2)” ofFIG. 6. In this case, the 3D virtual space rendering unit 1362 krotationally moves the position of a point of view to (1) to (9) so thatthe parallactic angle can be changed by “1°” centering on the center(gravity center) of volume data, and generates nine parallax imagesbetween which the parallactic angle differs from each other by 1° by theperspective projection method. Further, when the perspective projectionmethod is performed, the 3D virtual space rendering unit 1362 k sets apoint light source or a surface light source, which three-dimensionallyemits light in a radial manner centering on a line-of-sight direction,at each point of view. Further, when the perspective projection methodis performed, the points of view (1) to (9) may be parallel-shiftedaccording to the rendering condition.

Further, the 3D virtual space rendering unit 1362 k may perform thevolume rendering process using the parallel projection method and theperspective projection method together by setting a light source thattwo-dimensionally emits light in a radial manner centering on theline-of-sight direction on a longitudinal direction of a volumerendering image to display, and emits a parallel beam in theline-of-sight direction from infinity on a transverse direction of avolume rendering image to display.

The nine parallax images generated in the above-described way configurea parallax image group. In the first embodiment, for example, the nineparallax images are converted into interim images arranged in apredetermined format (for example, a lattice form) by the control unit135, and then output to the display unit 132 serving as the stereoscopicdisplay monitor. At this time, the operator of the workstation 130 canperform an operation of generating a parallax image group while checkinga stereoscopically viewable medical image displayed on the stereoscopicdisplay monitor.

The example of FIG. 6 has been described in connection with the case inwhich the projection method, the reference point-of-view position, andthe parallactic angle are received as the rendering condition. However,similarly even when any other condition is received as the renderingcondition, the 3D virtual space rendering unit 1362 k generates theparallax image group while reflecting each rendering condition.

Subsequently, the parallax image group which the 3D image processingunit 1362 has generated based on the volume data is regarded as anunderlay. Then, an overlay in which a variety of information (a scale, apatient name, an inspection item, and the like) is represented issuperimposed on the underlay, so that a 2D output image is generated.The 2D image processing unit 1363 is a processing unit that performsimage processing on the overlay and the underlay and generates a 2Doutput image, and includes a 2D object rendering unit 1363 a, a 2Dgeometric transform processing unit 1363 b, and a brightness adjustingunit 1363 c as illustrated in FIG. 5. For example, in order to reduce aload required in a process of generating a 2D output image, the 2D imageprocessing unit 1363 generates nine 2D output images by superimposingone overlay on each of nine parallax images (underlays). In thefollowing, an underlay on which an overlay is superimposed may bereferred to simply as a “parallax image.”

The 2D object rendering unit 1363 a is a processing unit that renders avariety of information represented on the overlay. The 2D geometrictransform processing unit 1363 b is a processing unit thatparallel-shifts or rotationally moves the position of a variety ofinformation represented on the overlay, or enlarges or reduces a varietyof information represented on the overlay.

The brightness adjusting unit 1363 c is a processing unit that performsa brightness converting process. For example, the brightness adjustingunit 1363 c adjusts brightness of the overlay and the underlay accordingto an image processing parameter such as gradation of a stereoscopicdisplay monitor of an output destination, a window width (WW), or awindow level (WL).

The two-dimensional images to be output that are generated in thismanner are temporarily stored in the storage unit 134 by the controlunit 135, for example, and are transmitted to the image storage device120 via the communication unit 133. If the terminal device 140 acquiresthe two-dimensional images to be output from the image storage device120, converts the two-dimensional images into an intermediate image inwhich the two-dimensional images are arranged in a predetermined format(for example, a lattice form), and displays the intermediate image onthe stereoscopic display monitor, for example, the doctor or thelaboratory technician who is the observer can browse the medical imagecapable of being viewed stereoscopically with the various types ofinformation (e.g., a scale, a patient's name, and an examination item)depicted thereon.

The configuration of the workstation 130 according to the presentembodiment has been described so far. Through this configuration, theworkstation 130 according to the present embodiment can improve a degreeof the depth of a stereoscopically viewable image according to controlof the control unit 135, which will be described in detail below. In thefollowing, a stereoscopically viewable image is sometimes referred to asa stereoscopic image.

Here, first, a degree of the depth of the stereoscopic image in therelated art will be described. FIG. 7 is a first diagram for describinga problem of the related art. FIG. 7 illustrates an example in which aunit pixel group is configured with pixels 1 to 9, and a stereoscopicimage is displayed such that nine parallax images generated with aparallactic angle “1°” are output with corresponding pixel values fromthe respective pixels. As illustrated in FIG. 7, when a stereoscopicimage is displayed by nine parallax images generated with a parallacticangle “1°,” since parallax is small, information of the depth includedin the nine parallax images is small, and thus a degree of the depth ofthe stereoscopic image to be displayed is lowered.

In this regard, when the parallactic angle increases, the information ofthe depth included in the nine parallax images increases, and a degreeof the depth increases, but there is a problem in that an image isblurred. FIG. 8 is a second diagram for describing a problem of therelated art. FIG. 8 illustrates an example in which a unit pixel groupis configured with pixels 1 to 9, and a stereoscopic image is displayedsuch that nine parallax images generated with a parallactic angle “2°”are output with corresponding pixel values from the respective pixels.As illustrated in FIG. 8, when a stereoscopic image is displayed by nineparallax images generated with a parallactic angle “2°,” since an angledifference between parallax images output from neighboring pixels islarge, a displayed stereoscopic image is blurred.

In other words, in the related art, there is a certain limit to a degreeof the depth of a stereoscopic image having no blur. For example, atechnique of increasing the resolution is considered as a solution tothis problem. FIG. 9 is a diagram for describing an example of atechnique of improving a degree of the depth of a stereoscopic imagehaving no blur. As illustrated in FIG. 9, for example, as a technique ofincreasing the resolution, a unit pixel group includes pixels 1 to 18.In this case, when eighteen parallax images generated with a parallacticangle “1°” are output with corresponding pixel values from therespective pixels, a stereoscopic image that has an improved degree ofthe depth and has no blur can be displayed.

However, an increase in the resolution by the hardware methodillustrated in FIG. 9 causes a technical problem and is not easy toimplement. In this regard, in this disclosure, a degree of the depth ofa stereoscopic image having no blur can be improved by control of thecontrol unit 135 illustrated in FIG. 4 without increasing the resolutionby the hardware method. In this regard, the control unit 135 accordingto the first embodiment will be described below in detail. FIG. 10 is adiagram for describing a configuration example of the control unit 135according to the first embodiment. As illustrated in FIG. 10, thecontrol unit 135 includes a rendering control unit 1351 and a displaycontrol unit 1352.

The rendering control unit 1351 performs control such that parallaximages of point-of-view positions which are larger in number than thenumber of pixels included in a unit pixel group to simultaneouslydisplay a plurality of parallax images are generated as a parallax imagegroup displayed by the unit pixel group. Specifically, the renderingcontrol unit 1351 controls the rendering processing unit 136 such thatthe volume rendering process is executed at point-of-view positionswhich are equal in number to an integral multiple of a parallax numberdisplayable by the display unit 132.

FIG. 11 is a diagram for describing an example of a process performed bythe rendering control unit 1351 according to the first embodiment. Forexample, when the display unit 132 can display a parallax image grouphaving nine parallaxes, the rendering control unit 1351 controls therendering processing unit 136 such that eighteen parallax images havinga parallactic angle difference of “1°” therebetween are generated byrotate the point-of-view position from the reference point-of-viewposition to (1) through (18) at parallactic angle intervals of “1°”centering on the center (gravity center) of volume data as illustratedin FIG. 11. FIG. 11 has been described in connection with the example inwhich a parallax image is generated using a perspective projectionmethod. However, an embodiment is not limited to this example, and, forexample, a parallax image may be generated using a parallel projectionmethod.

Referring back to FIG. 10, the display control unit 1352 performscontrol such that a plurality of parallax images whose point-of-viewpositions are adjacent to each other in the parallax image groupgenerated by control of the rendering control unit 1351 are displayed bythe same pixels while switching the plurality of parallax images at anarbitrary switching speed. Specifically, the display control unit 1352switches a plurality of parallax images whose point-of-view positionsare adjacent to each other so that a single parallax image is displayed,for example, 60 times for one second. An example of a process performedby the display control unit 1352 will be described below with referenceto FIGS. 12A and 12B.

FIG. 12A is a diagram for describing an example of a first displayprocess performed by the display control unit 1352 according to thefirst embodiment. FIG. 12A illustrates a process in which eighteenparallax images illustrated in FIG. 11 are generated by control of therendering control unit 1351, and then the images are displayed thenine-parallax display unit 132. Here, “T1” illustrated in FIG. 12Arepresents a time phase of a display start.

For example, the display control unit 1352 first performs control suchthat among parallax images generated at point-of-view positions (1) to(18), parallax images of positions (1), (3), (5), (7), (9), (11), (13),(15), and (17) are displayed through pixels 1, 2, 3, 4, 5, 6, 7, 8 and9, respectively, as illustrated in the time phase “T1” of FIG. 12A. Inother words, the display control unit 1352 performs control such thatpixel values corresponding to the parallax images of the positions (1),(3), (5), (7), (9), (11), (13), (15), and (17) are output from thepixels 1, 2, 3, 4, 5, 6, 7, 8, and 9, respectively.

Then, the display control unit 1352 switches the parallax images to bedisplayed through the pixels 1, 2, 3, 4, 5, 6, 7, 8, and 9 at anarbitrary switching speed. FIG. 12B is a diagram for describing anexample of a second display process performed by the display controlunit 1352 according to the first embodiment. FIG. 12B illustrates aprocess after the display process illustrated in FIG. 12A is performed.Here, “T2” illustrated in FIG. 12B represents a time phase next to “T1”when switching is performed at an arbitrary switching speed.

For example, the display control unit 1352 switches the parallax imagesto be displayed through the pixels 1, 2, 3, 4, 5, 6, 7, 8, and 9 toparallax images of the positions (2), (4), (6), (8), (10), (12), (14),(16), and (18) at an arbitrary switching speed, respectively, asillustrated in the time phase “T2” of FIG. 12B. Then, the displaycontrol unit 1352 displays the parallax image groups represented by thetime phases “T1” and “T2” of FIG. 12B through the pixels 1, 2, 3, 4, 5,6, 7, 8, and 9 while alternately switching the parallax image groups atan arbitrary switching speed.

Here, the display control unit 1352 switches the parallax image groupsdisplayed, for example, at the speed of once per 1/120 seconds as thearbitrary switching speed. In other words, the display control unit 1352causes the display unit 132 to display the parallax image groups at thefrequency of 120 Hz. This corresponds to a state in which among theeighteen parallax images, the nine parallax images represented by eachof the time phases “T1” and “T2” are being displayed at 60 Hz, and meansthat an image is displayed in the same state as the current state inwhich the parallax image group is being displayed at the frequency of 60Hz at normal times (when switching is not performed).

As described above, the workstation 130 according to the firstembodiment divides the parallax image group generated at thepoint-of-view positions which are larger in number than a parallaxnumber supported by the display unit 132 into groups of parallax numberunits, and displays each of the groups while switching each of thegroups at an arbitrary switching speed. Thus, a stereoscopic imageincluding more information about the depth direction than in the relatedart can be displayed, and a degree of the depth of a stereoscopic imagehaving no blur can be improved without increasing the resolution by thehardware method.

Further, as described above, in the present disclosure, a degree of thedepth can be improved by a software method, and thus an implementationthereof can be easily made. Further, for example, a depth increasingmode to increase a degree of the depth may be set. In this case, whenthe observer observes a medical image, the observer can cause theabove-described process to be executed by turning the depth increasingmode on.

Next, a process of the workstation 130 according to the first embodimentwill be described with reference to FIG. 13. FIG. 13 is a flow chartillustrating a procedure of a process performed by the workstation 130according to the first embodiment. As illustrated in FIG. 13, in theworkstation 130 according to the first embodiment, when the depthincreasing mode is turned on (Yes in step S101), the rendering controlunit 1351 controls the rendering processing unit 136 such that parallaximages are generated at point-of-view positions which are equal innumber to an n multiple of the number of pixels (step S102).

Then, the display control unit 1352 causes the n parallax images whichare adjacent to one another to be displayed through the same pixelswhile alternately switching the n parallax images at an arbitraryswitching speed (step S103). Thereafter, when the depth increasing modeis turned off or when an end command is received, the display controlunit 1352 ends the process. Meanwhile, the rendering control unit 1351is on standby until the depth increasing mode is turned on (No in stepS101).

As described above, according to the first embodiment, the display unit132 displays a predetermined number of parallax images. The renderingcontrol unit 1351 performs control such that a group of parallax imagesof point-of-view positions which are larger in number than thepredetermined number are generated. The display control unit 1352classifies a group of parallax images generated by control of therendering control unit 1351 into a first parallax image sub groupincluding a set of parallax images whose point-of-view positions arediscontinuous to each other and a second parallax image sub groupincluding parallax images whose respective point-of-view positions arebetween the respective parallax images of the set, and performs controlssuch that the display unit 132 displays the first parallax image subgroup and the second parallax image sub group while switching the firstparallax image sub group and the second parallax image sub group at apredetermined switching speed. Thus, the workstation 130 according tothe first embodiment can display a stereoscopic image including moreinformation about the depth direction than in the related art, and canimprove a degree of the depth of a stereoscopic image having no blurwithout increasing the resolution by the hardware method.

Further, according to the first embodiment, the display control unit1352 switches a plurality of parallax images whose point-of-viewpositions are adjacent to each other such that a single parallax imageis displayed 60 times for one second. Thus, the workstation 130according to the first embodiment can display an image in the samedisplay state as the normal display.

Second Embodiment

The first embodiment has been described in connection with the exampleof displaying parallax images having different point-of-view positionsthrough the same pixel while switching the parallax images. A secondembodiment will be described in connection with an example in whichdeviation between the parallax images displayed through the same pixelis corrected and then displayed. Further, in the second embodiment, thesame configuration as the control unit 135 of FIG. 10 according to thefirst embodiment is provided. In the second embodiment, a control unitthat corrects deviation between parallax images displayed through thesame pixel is referred to as a display control unit 1352 a. In otherwords, the display control unit 1352 a has a configuration in which anew process is added to the display control unit 1352 illustrated inFIG. 10.

Here, first, an outline of a correction process executed by the displaycontrol unit 1352 a will be described with reference to FIG. 14. FIG. 14is a schematic view for describing an outline of a process executed bythe display control unit 1352 a according to the second embodiment. FIG.14 illustrates pixels to output when eighteen parallax imagesillustrated in FIG. 11 are displayed by performing switching in units ofnine parallax images.

For example, in the time phase “T1”, the display control unit 1352according to the first embodiment causes parallax images of positions(1), (3), (5), (7), (9), (11), (13), (15), and (17) to be displayedthrough pixels 1, 2, 3, 4, 5, 6, 7, 8, and 9, respectively, asillustrated in FIG. 14(A). Further, in the time phase “T2”, the displaycontrol unit 1352 according to the first embodiment causes parallaximages of positions (2), (4), (6), (8), (10), (12), (14), (16), and (18)to be displayed through the pixels 1, 2, 3, 4, 5, 6, 7, 8, and 9,respectively, as illustrated in FIG. 14(A).

Here, in case of the pixel 1, the parallax image of the position (1) isdisplayed in the time phase “T1”, and the parallax image of the position(2) is displayed in the time phase “T2.” In other words, deviationcorresponding to a parallactic angle “1°” occurs between the parallaximages displayed through the same pixel. Here, when the observeractually observes a medical image, it is not easy for the observer toobserve without any movement, and slightly deviated parallax enters theeyes due to high-speed switching. Thus, a state close to a state inwhich eighteen parallaxes are input by a hardware method is created.

Further, the display control unit 1352 a according to the secondembodiment can perform control such that each of the parallax images tobe displayed is displayed to straddle between neighboring pixels asillustrated in the time phase “T2” in FIG. 14(B). For example, asillustrated in FIG. 14(B), the display control unit 1352 a can performcontrol such that the parallax image of the point-of-view position (2)is displayed through the pixels 1 and 2.

Specifically, the display control unit 1352 a calculates a value of halfa pixel value which is supposed to be output from each pixel for eachpixel. Then, in order to cause each parallax image to be displayed tostraddle between neighboring pixels, the display control unit 1352 aaccumulates the calculated value of half the pixel value for each pixel,and then performs controls such that an accumulated cumulative value isoutput from each pixel as a new pixel value.

FIG. 15 is a diagram for describing an example of a process performed bythe display control unit 1352 a according to the second embodiment. FIG.15 illustrates a processing example of the display control unit 1352 aon one unit pixel group when the eighteen parallax images illustrated inFIG. 11 are displayed through the display unit 132. Even though notillustrated, the display control unit 1352 a performs the followingprocess on all of unit pixel groups supported by the display unit 132.

For example, the display control unit 1352 a first extracts pixel valuescorresponding to the parallax images to be displayed through a certainunit pixel group as illustrated in FIG. 15(A). Then, the display controlunit 1352 a determines pixel values to be output from the respectivepixels in the time phase “T1” and the time phase “T2” as illustrated inFIG. 15(B).

Here, the display control unit 1352 a calculates a value of half thepixel value for parallax image group of the time phase in whichdeviation is to be corrected, and calculates a cumulative value to whichthe calculated value is added for each pixel. For example, the displaycontrol unit 1352 a sets the time phase “T2” as a correction target, andcalculates a value of half the pixel value, that is, calculates 15(=30/2) for the position (2), 25 (=50/2) for the position (4), 15(=30/2) for the position (6), and the like as illustrated in FIG. 15(C).

Then, the display control unit 1352 a sets the calculated value which ishalf the pixel value as an addition value on the neighboring pixel. Forexample, the display control unit 1352 a sets the value “15” calculatedbased on the pixel value “30” for the position (2) as the addition valuefor the pixel value “50” of the position (4) as illustrated in FIG.15(C). Here, the additional value is set only to a pixel that straddlesbetween pixels. For example, in the pixels 1 and 2 illustrated in FIG.14(B), half the parallax image of the position (2) to be output from thepixel 1 is output from the pixel 2. Thus, the pixel value “30” of theposition (2) to be output through the pixel 1 is converted into “15”which is a half (½) thereof as illustrated in FIG. 15(C). Meanwhile, inthe pixel 2, the pixel value “50” of the position (4) is converted into“25” which is a half (½) thereof, but since “15” which is half the pixelvalue “30” of the position (2), “15” is set as the additional value.Further, in the pixel 1, “0” is set as the additional value since thepixel value corresponding to another parallax image is not output.

Then, the display control unit 1352 a calculates the cumulative valuefor each pixel by adding the additional value to the calculated valuewhich is half the pixel value. For example, the display control unit1352 a calculates “40 (=25+15)” as the cumulative value of the pixel 2as illustrated in FIG. 15(C). Then, the display control unit 1352 adetermines the calculated cumulative values as pixel values to be outputthrough the respective pixel in the time phase of the correction target.For example, the display control unit 1352 a determines 15 for the pixel1, 40 for the pixel 2, 40 for the pixel 3, and the like as the pixelvalues to be output through the respective pixels in the time phase “T2”as illustrated in FIG. 15(D).

Thereafter, the display control unit 1352 a performs control such thatthe pixel values which are not the correction target and the determinedpixel values are output from the respective pixels while beingalternately switched at an arbitrary switching speed (for example, onceper 1/120 seconds).

The second embodiment has been described in connection with the examplein which the time phase “T2” is the correction target. However, anembodiment is not limited to this example, and for example, the timephase “T1” may be the correction target. In this case, the displaycontrol unit 1352 a corrects the pixel values such that the parallaximage group of the time phase “T1” illustrated in FIG. 14(A) is whollyslid to the left.

Next, a process of the workstation 130 according to the secondembodiment will be described with reference to FIG. 16. FIG. 16 is aflow chart illustrating a procedure of a process performed by theworkstation 130 according to the second embodiment. As illustrated inFIG. 16, in the workstation 130 according to the second embodiment, whenthe depth increasing mode is turned on (Yes in step S201), the renderingcontrol unit 1351 controls the rendering processing unit 136 such thatparallax images are generated at point-of-view positions which are equalin number to an n multiple of the number of pixels (step S202).

Then, the display control unit 1352 a determines whether or not thecorrection mode has been turned on (step S203). Here, when it isdetermined that the correction mode has been turned on (Yes in stepS203), the display control unit 1352 a calculates a value which is halfa pixel value of each of the parallax images to be displayed in the timephase of the correction target (step S204).

Thereafter, the display control unit 1352 a calculates a cumulativevalue to which the calculated value is added (step S205), and outputsthe pixel value of each of the parallax images to be displayed in thetime phase of the correction target and the calculated cumulative valuethrough the same pixel while alternately switching the pixel value andthe cumulative value at an arbitrary switching speed (step S206).

However, when it is determined in step S203 that the correction mode hasnot been turned on (No in step S203), the display control unit 1352 aoutputs the pixel values of the n parallax images which are adjacent toeach other through the same pixels while alternately switching the pixelvalues of the n neighboring parallax images at an arbitrary switchingspeed (step S207). Thereafter, when the depth increasing mode is turnedoff or when the end command is received, the display control unit 1352 aends the process. Further, the rendering control unit 1351 is on standbyuntil the depth increasing mode is turned on (No in step S201).

As described above, according to the second embodiment, the displaycontrol unit 1352 a performs control such that among a plurality ofparallax images to be displayed through the same pixels, at least oneparallax image is displayed to straddle between the neighboring pixels.Thus, the workstation 130 according to the second embodiment can correctdeviation between the point-of-view positions of the parallax images tobe displayed through the same pixel, improve a degree of the depth, anddisplay a high-resolution stereoscopic image.

Third Embodiment

The first and second embodiments have been described so far, but besidesthe first and second embodiments, various different embodiments may bemade.

The second embodiment has been described in connection with the examplein which deviation of the parallax image is corrected using the pixelvalue. However, deviation of the parallax image can be corrected suchthat a lenticular lens is slid in synchronization with a switchingtiming of the parallax image. FIG. 17 is a diagram for describingdeviation correction by sliding a lenticular lens according to a thirdembodiment. FIG. 17 illustrates an example in which a lenticular lens isslid when the parallax images illustrated in FIG. 12B are switched.

When deviation is corrected by sliding a lenticular lens, for example,the display unit 132 includes a driving device that slides a lenticularlens. For example, the display unit 132 includes a vibration generatingdevice or the like as the driving device. The control unit 135synchronizes a switching frequency of the parallax image with avibration frequency of the vibration generating device based on areference signal such as a clock.

In this way, the lenticular lens is slid in synchronization withswitching from the parallax images of the time phase “T1” illustrated inFIG. 17(A) to the parallax images of the time phase “T2” illustrated inFIG. 17(B), for example, as illustrated in FIG. 17. For example, whenthe lenticular lens is slid as indicated by an arrow 20 of FIG. 17(B),an advancing direction of light that has passed through the lenticularlens changes. Through this operation, deviation between thepoint-of-view positions of the parallax images can be corrected.

Further, the vibration frequency of the vibration generating device maybe synchronized with the switching frequency of the parallax image bymanually changing the vibration frequency of the vibration generatingdevice. For example, the display unit 132 may be provided with a dialused to change the vibration frequency of the vibration generatingdevice. The observer can correct deviation between the point-of-viewpositions of the parallax images by operating the dial while observingthe stereoscopic image.

Further, the above-described embodiments have been described inconnection with the example in which the eighteen parallax images aregenerated from the volume data, and the generated eighteen parallaximages are displayed such that switching is performed units of nineparallax images. However, an embodiment is not limited to this example,and an arbitrary number of parallax images may be used to the extentthat the number of parallax image is an integral multiple of a parallaxnumber. For example, 36 parallax images may be generated from volumedata, and the generated 36 parallax images may be displayed such thatswitching is performed units of nine parallax images. In this case, thedisplay unit 132 is set to perform a display at 240 Hz.

Further, the above-described embodiments have been described inconnection with the example in which the workstation 130 executes therendering process on the volume data, and displays the generatedparallax image. However, the disclosed technology is not limited to thisexample. For example, the medical image diagnosis apparatus 110 executesthe rendering process on the volume data, and displays the generatedparallax image. Further, either the medical image diagnosis apparatus110 or the workstation 130 may execute the rendering process on thevolume data, and the terminal device 140 may display the image.

Further, the above-described embodiments have been described inconnection with the example in which the terminal device 140 displaysthe medical image acquired from the image storage device 120. However,the disclosed technology is not limited to this example. For example,the terminal device 140 may be connected directly to the medical imagediagnosis apparatus 110 or the workstation 130.

Further, the above-described embodiments have been described inconnection with the example in which the workstation 130 acquires thevolume data from the image storage device 120, and executes therendering process on the volume data. However, the disclosed technologyis not limited to this example. For example, the workstation 130 mayacquire the volume data from the medical image diagnosis apparatus 110,and execute the rendering process on the volume data.

As described above, according to the embodiments, the image processingsystem, apparatus and method and the medical image diagnosis apparatusof the present embodiment can improve a degree of the depth of thestereoscopically viewable image.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

What is claimed is:
 1. An image processing system, comprising: a displayconfigured to display a stereoscopic image by arranging parallax imagesgenerated by performing a volume rendering process on volume data whilesequentially changing a point-of-view position by a predeterminedparallactic angle with a same number of pixels as a number ofpoint-of-view positions, and outputting the arranged parallax images;and a processing circuit configured to generate different parallaximages which are an integer multiple of the number of pixels byperforming the volume rendering process on the volume data atpoint-of-view positions which are the integer multiple of the number ofpixels when receiving an operation to change to a predetermined mode,classify the generated different parallax images that are the integermultiple of the number of pixels into a first parallax image sub groupto be a set of parallax images whose point-of-view positions arediscontinuous to each other and a same in number as the number of pixelsand a second parallax image sub group including a set of parallax imageswhose point-of-view positions are between the point-of-view positions ofthe first parallax image sub group and a same in number as the number ofpixels, and perform control such that the display continuously displaysthe first parallax image sub group and the second parallax image subgroup while alternately switching the first parallax image sub group andthe second parallax image sub group at a predetermined switching speedwhile in the predetermined mode.
 2. The image processing systemaccording to claim 1, wherein the processing circuit performs controlsuch that the first parallax image sub group and the second parallaximage sub group are switched and displayed such that each of theparallax images included in the first parallax image sub group and thesecond parallax image sub group is displayed an arbitrary number oftimes for one second.
 3. The image processing system according to claim1, wherein the processing circuit classifies a plurality of parallaximage sub groups obtained by classifying parallax images whosepoint-of-view positions are between the point-of-view positions of thefirst parallax image sub group into different parallax image sub groupsas the second parallax image sub group, and performs control such thatthe first parallax image sub group and the parallax image sub groupsincluded in the second parallax image sub group are sequentiallyswitched and displayed.
 4. The image processing system according toclaim 1, wherein the processing circuit generates an interim imageobtained by averaging pixel values of a plurality of parallax imagesincluded in either of the first parallax image sub group and the secondparallax image sub group from the plurality of parallax images on aportion in which the point-of-view positions of a plurality of parallaximages included in the first parallax image sub group and thepoint-of-view positions of a plurality of parallax images included inthe second parallax image sub group are alternately continuous betweenthe parallax image sub groups, and performs control such that thedisplay displays the generated interim image instead of the plurality ofparallax images while switching the interim image at a predeterminedswitching speed.
 5. An image processing apparatus, comprising: a displayconfigured to display a stereoscopic image by arranging parallax imagesgenerated by performing a volume rendering process on volume data whilesequentially changing a point-of-view position by a predeterminedparallactic angle with a same number of pixels as a number ofpoint-of-view positions, and outputting the arranged parallax images;and a processing circuit configured to generate different parallaximages which are an integer multiple of the number of pixels byperforming the volume rendering process on the volume data atpoint-of-view positions which are the integer multiple of the number ofpixels when receiving an operation to change to a predetermined mode,classify the generated different parallax images that are the integermultiple of the number of pixels into a first parallax image sub groupto be a set of parallax images whose point-of-view positions arediscontinuous to each other and a same in number as the number of pixelsand a second parallax image sub group including a set of parallax imageswhose point-of-view positions are between the point-of-view positions ofthe first parallax image sub group and a same in number as the number ofpixels, and perform control such that the display continuously displaysthe first parallax image sub group and the second parallax image subgroup while alternately switching the first parallax image sub group andthe second parallax image sub group at a predetermined switching speedwhile in the predetermined mode.
 6. An image processing method,comprising: generating, by a processing circuit, different parallaximages which are an integer multiple of the number of pixels byperforming the volume rendering process on the volume data atpoint-of-view positions which are the integer multiple of the number ofpixels when receiving an operation to change to a predetermined mode;and classifying, by a processing circuit, the generated differentparallax images which are the integer multiple of the number of pixelsinto a first parallax image sub group to be a set of parallax imageswhose point-of-view positions are discontinuous to each other and a samein number as the number of pixels and a second parallax image sub groupincluding a set of parallax images whose point-of-view positions arebetween the point-of-view positions of the first parallax image subgroup and a same in number as the number of pixels, and performingcontrol, by the processing circuit, such that a display that displays astereoscopic image by arranging parallax images generated by performingthe volume rendering process on the volume data while sequentiallychanging a point-of-view position by a predetermined parallactic anglewith a same number of pixels as a number of point-of-view positions, andoutputting the arranged parallax images, continuously displays the firstparallax image sub group and the second parallax image sub group whilealternately switching the first parallax image sub group and the secondparallax image sub group at a predetermined switching speed while in thepredetermined mode.
 7. A medical image diagnosis apparatus, comprising:a display configured to display a stereoscopic image by arrangingparallax images generated by performing a volume rendering process onvolume data while sequentially changing a point-of-view position by apredetermined parallactic angle with a same number of pixels as a numberof point-of-view positions, and outputting the arranged parallax images;and a processing circuit configured to generate different parallaximages which are an integer multiple of the number of pixels byperforming the volume rendering process on the volume data atpoint-of-view positions which are the integer multiple of the number ofpixels when receiving an operation to change to a predetermined mode,classify the generated different parallax images that are the integermultiple of the number of pixels into a first parallax image sub groupto be a set of parallax images whose point-of-view positions arediscontinuous to each other and a same in number as the number of pixelsand a second parallax image sub group including a set of parallax imageswhose point-of-view positions are between the point-of-view positions ofthe first parallax image sub group and a same in number as the number ofpixels, and perform control such that the display continuously displaysthe first parallax image sub group and the second parallax image subgroup while alternately switching the first parallax image sub group andthe second parallax image sub group at a predetermined switching speedwhile in the predetermined mode.